The present invention relates to dental floss and, in particular, relates to a dental floss comprised of aromatic polyamide fibers having at least 85 percent of the amide linkages attached directly to two aromatic rings.
The use of dental floss is essential to oral health. Dental floss functions to cleanse dental or bacterial plaque from certain critically important areas in dentition and supporting structures surrounding the teeth. Bacterial plaque is comprised of salivary biproducts, dead epithelial cells and bacteria. Bacterial plaque organizes into colonies on the surface of the tooth within 24 to 36 hours irrespective of nutrient intake. Upon contact with carbohydrates, the bacterial colonies form acids which cause destruction of the tooth structure. Bacterial colonies also produce bacterial toxins which, in some cases, cause periodontal disease or pyorrhea. This disease results in inflamed gum tissues which, in some cases, causes recession and destruction of the supporting bone of the tooth or teeth.
These problems can be avoided by daily mechanical disruption of the plaque. Disruption of the plaque functions to disperse the bacterial colonies, thereby preventing the formation of concentrated solutions of acid and bacterial toxins. On most of the dental surface area, bacterial colonies can be disturbed by regular brushing with a tooth brush. Unfortunately, brushing does not disturb bacterial plaque disposed in sheltered or tightly contacting areas of adjacent teeth. Dental floss functions to disturb the colonies of bacteria in these areas.
Dental floss should exhibit certain physical and mechanical properties to enable its use in dental hygiene. Dental floss should possess a high tensile strength or tenacity and should be capable of retaining its tenacity when wet. The dental floss should be heat stable to enable sterilization. Dental floss should not be abrasive enough to cause destruction of the supporting structure of the dentition with continuous use.
One prior dental floss is comprised of silk fibers. Silk has a comparatively low tenacity, which results in frequent breakage during use. Furthermore, the tenacity decreases upon the wetting of the floss thereby enhancing the probability of breakage. Since flossing of the dentition is at best a tedious chore, frequent breakage of the floss during use causes frustration to the user which will, in many cases, result in eventual discontinuation of the use of dental floss. This motivational problem has, in the past, prevented widespread use of dental floss.
Another prior dental floss is comprised of nylon. Nylon also has a comparatively low tenacity which again results in frequent breakage of the floss during use. The tenacity of nylon also decreases upon wetting with saliva thereby enhancing the probability of breakage. In order to prevent the snagging and breaking of the nylon fibers in interstices between the teeth, nylon floss has, in the past, been provided with a lubricant such as a resinous agent or paraffin. The lubricant aids in preventing snagging of the fiber in tight contact areas. Unfortunately, the lubricant becomes displaced onto the surface of the tooth causing a subsequent build-up of a pg,4 sticky film which acts as a substrate for bacterial growth. The lubricant also prevents the flaring or spreading of the fibers of the floss over the surface of the tooth during use. It is preferred that during use the fibers of the floss spread out on the surface of the tooth thereby enabling every fiber to contact the surface of the tooth. The flaring of the floss over the surface of the tooth enables more efficient disruption of the bacterial plaque. Nylon floss is also abrasive enough that in some cases, it causes partial destruction of the supporting root structure of dentition with continuous use. Nylon polymer is not heat stable enough to enable sterilzation of the floss.